Anti-airlock low-leakage oil well pump

Abstract

The invention provides an anti-airlock low-leakage oil well pump, and belongs to the technical field of mechanical oil extraction in the oilfield development process. The device comprises an upper connector, an upper outer pipe, a short plunger structure, a pump cylinder, a replacement cavity pipe, a Tesla valve plate set and a sealing assembly. The upper connector abuts against the upper portion of the upper outer pipe. An annular gas-liquid replacement cavity is defined by the pump cylinder, the replacement cavity pipe, the Tesla valve block set and the sealing assembly, the gas-liquid replacement cavity is located on the upper portion of the pump cylinder and communicates with the pump cylinder, and an annular space is formed by the gas-liquid replacement cavity, the pump cylinder and the upper outer pipe. The short plunger structure comprises a sealing sleeve assembly, an adjusting back cap and a short plunger, the short plunger structure is located in the replacement cavity pipe, and the sealing sleeve assembly, the adjusting back cap and the short plunger are sequentially arranged from top to bottom. According to the invention, the occurrence probability of airlock is reduced, the working stability and efficiency of the pump are improved, the stroke loss is reduced, and the overall working efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mechanical oil production in oilfield development, and particularly relates to a low leakage and air lock preventing oil well pump. BACKGROUND

[0002] In recent years, gas drive technology has become an important technical means for improving recovery rate of conventional oil reservoirs in the later stage and unconventional resources. Pilot tests and industrial applications of gas drive technology such as natural gas drive, CO2 drive and air drive have been carried out in domestic Xinjiang, Daqing, Jilin and other oilfields. The production well output fluid in the gas drive process often shows problems such as large fluctuation, discontinuous liquid supply and high gas-liquid ratio (usually > 500).

[0003] The gas lock problem is prone to occur in the production process of the oil well pump of the oil well with high gas-liquid ratio, which leads to the decrease of the production efficiency of the oil well, and even causes the shutdown of the oil well. The cause of the gas lock phenomenon is mainly related to the relationship between the bottom hole pressure and the saturation pressure. In the production process of the oil well, since the current standard oil well pump has a certain leakage, when the bottom hole pressure is lower than the saturation pressure, the separated gas in the crude oil will separate out from the liquid phase. Part of the separated gas will accumulate in the annular space of the oil sleeve to form the casing pressure. The casing pressure that is too high will cause the decline of the dynamic liquid level, and when the dynamic liquid level drops to the suction inlet of the oil well pump, the gas will flow into the oil well pump, which will reduce the pump efficiency and thus affect the production of the oil well.

[0004] According to the oil industry standard of the oil well pump, there is a reasonable gap between the pump barrel and the plunger, and there is appropriate leakage. However, when the gas-liquid ratio is high and there is a large amount of dissolved gas in the crude oil, the crude oil leaks through the gap between the pump barrel and the plunger into the pump, the pressure decreases, the gas separates out and remains in the pump, which leads to the gas lock and reduces the pump efficiency, thus affecting the production of the oil well.

[0005] For the oil well with a large amount of gas, the gas lock and low pump efficiency are common production problems. The periodic occurrence of these problems will cause the oil well to be unable to produce normally for a period of time, which is a few hours or a few days. This intermittent oil production phenomenon not only wastes the energy of the oil pumping unit, but also increases the risk of frozen pipelines in severe cold weather.

[0006] The periodic gas lock failure of the plunger pump is the direct cause of the intermittent oil production. In this process, the accumulation and release of the gas will cause the decline of the working efficiency of the plunger pump, thus affecting the production of the oil well.

[0007] The current technical solution mainly adopts the oil well pump with the anti-gas function or the downhole gas-liquid separator to reduce the possibility of the gas entering the plunger pump, so as to prevent the gas lock phenomenon. However, due to the single structure and function of the current oil well pump, the problem of low pump efficiency still exists, and the gas lock phenomenon cannot be completely avoided, which seriously affects the yield and production efficiency of the oil well. SUMMARY

[0008] To solve the problems in the prior art, the present application aims to provide an anti-airlock low-leakage oil pumping pump, which significantly improves the mining efficiency under high gas-liquid ratio environment and solves the problems of airlock and low efficiency of traditional oil pumping pumps under such conditions.

[0009] The present application provides an anti-airlock low-leakage oil pumping pump for installation on a pipe string, comprising an upper joint, an upper outer pipe, a short plunger structure, a pump barrel, a displacement cavity pipe, a Tesla valve piece group and a sealing assembly.

[0010] The upper joint is in abutment with the upper portion of the upper outer pipe.

[0011] The pump barrel, the displacement cavity pipe, the Tesla valve piece group and the sealing assembly enclose an annular gas-liquid displacement cavity, which is located at the upper portion of the pump barrel and communicates with the pump barrel, and the gas-liquid displacement cavity, the pump barrel and the upper outer pipe form an annular space.

[0012] The short plunger structure comprises a sealing sleeve assembly, an adjusting back cap and a short plunger, and is located inside the displacement cavity pipe, with the sealing sleeve assembly, the adjusting back cap and the short plunger being arranged in sequence from top to bottom.

[0013] Preferably, the Tesla valve piece group is located at the bottom outside of the pump barrel.

[0014] Preferably, the Tesla valve piece group comprises a sealing compression cap, a valve piece shell, a valve piece and a lower outer pipe, which are arranged in sequence from top to bottom.

[0015] Preferably, a long slot is formed in the lower portion of the pump barrel, and a small hole is drilled in the valve piece shell to form an exhaust passage with the valve piece, and the flow channel is a Tesla valve structure.

[0016] Preferably, the exhaust passage is arranged into two groups at a preset angle, the two groups of valve pieces are stacked at a preset angle, a spacer is arranged between the two groups of valve pieces, and each two valve pieces and one spacer form a group, an internal series Tesla passage is formed in the group, and the Tesla valve is composed of multiple groups.

[0017] Preferably, the sealing assembly comprises a lower sealing joint, a compressible sealing ring and a sealing ring compression cap, which are all arranged on the outside of the pump barrel.

[0018] Preferably, the compressible sealing ring is arranged on the inside of the lower sealing joint, and the sealing ring compression cap is arranged below the lower sealing joint.

[0019] Preferably, the short plunger structure includes an upstream valve assembly, a core tube, a downstream valve assembly, a sealing sleeve assembly, an adjusting back cap, and a short plunger. The upstream valve assembly and the downstream valve assembly are respectively disposed at the upper and lower parts outside the core tube. The core tube is disposed inside the pump barrel. The sealing sleeve assembly, the adjusting back cap, the short plunger, and the sealing assembly are disposed between the upstream valve assembly and the downstream valve assembly.

[0020] Preferably, the upstream valve assembly includes an upstream moving valve, a valve cover, a first valve ball, and a first valve seat. The upstream moving valve, the valve cover, and the first valve seat are arranged sequentially from top to bottom outside the core tube, and the first valve ball is arranged inside the core tube.

[0021] Preferably, the sealing sleeve assembly, adjusting back cap, short plunger, and valve seat cap are arranged sequentially below the upstream valve assembly.

[0022] Preferably, the sealing sleeve assembly includes an outer sealing sleeve, an inner elastic sleeve, and a filler, wherein the filler is disposed between the outer sealing sleeve and the inner elastic sleeve.

[0023] Preferably, the outer sealing sleeve has an opening, allowing it to expand and contract elastically; the outer surface friction coefficient of the outer sealing sleeve is less than a preset friction coefficient; the hardness of the outer sealing sleeve is greater than a preset hardness; and the inner elastic sleeve has an opening, allowing it to expand and contract elastically.

[0024] Preferably, the downstream valve assembly includes a second valve ball, a second valve seat, a tailpipe connector, and a fixed valve assembly. The second valve ball is disposed within the fixed valve assembly, the tailpipe connector is disposed below the fixed valve assembly, and the second valve seat is disposed between the tailpipe connector and the fixed valve assembly.

[0025] Preferably, a set of sealing assemblies is provided below the upstream valve assembly and above the downstream valve assembly.

[0026] Preferably, the gas-liquid replacement chamber is located at the upper 1 / 3 of the pump cylinder.

[0027] Preferably, a middle sealing joint is provided between the upper outer tube and the replacement cavity tube, and a lower sealing joint is provided between the replacement cavity tube and the Tesla valve plate assembly.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) Anti-jamming performance: The short plunger structure design reduces the contact area with the pump barrel, thereby reducing the risk of jamming. The larger mating clearance and short mating surface length make it easier to release even if jamming occurs, and this design also helps to reduce manufacturing costs.

[0030] 2. Gas prevention effect: The reduction in leakage directly reduces the probability of gas lock, improving the pump's working stability and efficiency; the labyrinth valve design helps to accelerate the exhaust process, further improving the pump's gas handling capacity.

[0031] 3. Energy saving effect: Due to low leakage and high pump efficiency, energy consumption is low, resulting in good energy saving. Furthermore, the elastic seals used are resistant to high temperatures, corrosion, and wear, extending their service life.

[0032] 4. Reduced stroke loss: The design of the short gas-liquid displacement chamber reduces stroke loss and improves overall working efficiency. Attached Figure Description

[0033] Figure 1 This is a longitudinal sectional view of an anti-airlock, low-leakage oil pump according to an embodiment of the present invention;

[0034] Figure 2 for Figure 1 Longitudinal sectional view at point A;

[0035] Figure 3 for Figure 1 Cross-sectional view at point B;

[0036] Figure 4 This is a schematic diagram of the gas-liquid replacement chamber portion in one embodiment of the present invention;

[0037] Figure 5 This is a schematic diagram of a low-leakage short plunger structure according to an embodiment of the present invention;

[0038] Figure 6 This is a cross-sectional view of a valve plate in a Tesla valve plate assembly according to an embodiment of the present invention;

[0039] Figure 7 This is a cross-sectional view of a spacer in a Tesla valve assembly according to an embodiment of the present invention;

[0040] In the diagram, 1-upper connector, 2-upper outer pipe, 3-pump barrel, 4-middle sealing connector, 5-displacement chamber pipe, 6-lower sealing connector, 7-valve plate sealing cap, 8-valve plate housing, 9-valve plate, 10-lower outer pipe, 11-lower connector, 12-fixed valve assembly, 13-tail pipe connector, 14-sealing ring, 15-sealing ring cap, 16-second valve ball, 17-second valve seat, 18-upper moving valve, 19-valve cover, 20-first valve ball, 21-first valve seat, 22-core tube, 23-sealing sleeve assembly, 24-adjusting back cap, 25-short plunger, 26-valve seat cap, 27-outer sealing sleeve, 28-inner elastic sleeve, 29-filler; 30-spacer. Detailed Implementation

[0041] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0042] This invention provides an anti-airlock, low-leakage oil pump, which is used for installation on a tubing string and includes an upper connector 1, an upper outer tube 2, a short plunger structure, a pump barrel 3, a displacement chamber tube 5, a Tesla valve plate assembly, and a sealing assembly.

[0043] The upper connector 1 abuts against the upper part of the upper outer tube 2;

[0044] The pump cylinder 3, the displacement chamber tube 5, the Tesla valve plate group and the sealing assembly form an annular gas-liquid displacement chamber. The gas-liquid displacement chamber is located on the upper part of the pump cylinder 3 and is connected to the pump cylinder 3. The gas-liquid displacement chamber, the pump cylinder 3 and the upper outer tube 2 form an annular space.

[0045] The short plunger structure includes a sealing sleeve assembly 23, an adjusting back cap 24, and a short plunger 25. The short plunger structure is located inside the replacement chamber 5, and the sealing sleeve assembly 23, the adjusting back cap 24, and the short plunger 25 are arranged in order from top to bottom.

[0046] The double-layered gas-liquid replacement chamber, pump barrel 3, and upper outer pipe 2 form an annular space. The pump barrel 3 has elongated holes, which are located at the upper and lower parts of the gas-liquid replacement chamber. The pump barrel 3 is connected to the gas-liquid replacement chamber. When the gas-liquid ratio of the oil well is high, the pump barrel 3 has poor filling degree, with less liquid and more gas. When the short plunger 25 passes through the gas-liquid replacement chamber 15) on the upper stroke, the short plunger 25 is connected to the gas-liquid replacement chamber at the upper and lower parts by the elongated holes. The liquid in the upper part of the short plunger 25 enters the pump barrel 3 in the lower part of the short plunger. When the short plunger 25 passes through the gas-liquid replacement chamber on the lower stroke, the gas inside the pump barrel 3 is discharged to the upper part of the short plunger 25 through the gas-liquid replacement chamber. After several strokes, the gas is discharged and the gas lock is released.

[0047] According to one specific embodiment of the present invention, the Tesla valve assembly is located on the bottom outer side of the pump cylinder 3.

[0048] According to a specific embodiment of the present invention, the Tesla valve assembly includes a sealing cap 7, a valve housing 8, a valve 9, and a lower outer tube 10, wherein the sealing cap 7, the valve housing 8, the valve 9, and the lower outer tube 10 are arranged sequentially from top to bottom.

[0049] According to a specific embodiment of the present invention, the pump cylinder 3 has an elongated hole at the bottom, and the valve plate housing 8 has a small hole drilled on it to form an exhaust channel with the valve plate 9. The flow channel is a Tesla valve structure.

[0050] According to a specific embodiment of the present invention, the exhaust channels are arranged into two groups at a preset angle, the two groups of valve plates 9 are stacked at a preset angle, and a spacer is provided between the two groups of valve plates. Each group consists of two valve plates and a spacer, and a series Tesla channel is formed inside. The Tesla valve is composed of multiple groups, which can greatly lengthen the exhaust flow channel of the Tesla valve structure.

[0051] According to a specific embodiment of the present invention, the sealing assembly includes a lower sealing joint 6, a compressible sealing ring 14, and a sealing ring cap 15, all of which are disposed on the outside of the pump cylinder 3.

[0052] According to one specific embodiment of the present invention, the compressible sealing ring 14 is disposed inside the lower sealing joint 6, and the sealing ring cap 15 is disposed below the lower sealing joint 6. Adjusting the back cap 23 can adjust the clamping force of the sealing ring 14, allowing for some wobbling and a small axial clearance.

[0053] According to a specific embodiment of the present invention, the short plunger structure includes an upstream valve assembly, a core tube 22, a downstream valve assembly, a sealing sleeve assembly 23, an adjusting back cap 24, and a short plunger 25. The upstream valve assembly and the downstream valve assembly are respectively disposed at the upper and lower parts outside the core tube 22. The core tube 22 is disposed inside the pump barrel. The sealing sleeve assembly 23, the adjusting back cap 24, the short plunger 25, and the sealing assembly are disposed between the upstream valve assembly and the downstream valve assembly.

[0054] According to a specific embodiment of the present invention, the upstream valve assembly includes an upstream moving valve 18, a valve cover 19, a first valve ball 20, and a first valve seat 21. The upstream moving valve 18, the valve cover 19, and the first valve seat 21 are arranged sequentially from top to bottom outside the core tube 22, and the first valve ball 20 is arranged inside the core tube 22.

[0055] According to one specific embodiment of the present invention, the sealing sleeve assembly 23, the adjusting back cap 24, the short plunger 25 and the valve seat cap 26 are sequentially arranged below the upstream valve assembly.

[0056] According to a specific embodiment of the present invention, the sealing sleeve assembly 23 includes an outer sealing sleeve 27, an inner elastic sleeve 28, and a filler 29, wherein the filler 29 is disposed between the outer sealing sleeve 27 and the inner elastic sleeve 28.

[0057] According to a specific embodiment of the present invention, the outer sealing sleeve 27 is provided with an opening, which can elastically expand and contract. The outer surface friction coefficient of the outer sealing sleeve 27 is less than a preset friction coefficient, and the hardness of the outer sealing sleeve 27 is greater than a preset hardness, thereby improving the durability and efficiency of the pump. The inner elastic sleeve 28 is provided with an opening, which can elastically expand and contract, thereby helping to fit tightly against the pump cylinder 3, eliminating gaps, and reducing leakage.

[0058] According to a specific embodiment of the present invention, the downstream valve assembly includes a second valve ball 16, a second valve seat 17, a tailpipe connector 13, and a fixed valve assembly 12. The second valve ball 16 is disposed within the fixed valve assembly 12, the tailpipe connector 13 is disposed below the fixed valve assembly 12, and the second valve seat 17 is disposed between the tailpipe connector 13 and the fixed valve assembly 12.

[0059] According to one specific embodiment of the present invention, a set of sealing assemblies is provided below the upstream valve assembly and above the downstream valve assembly.

[0060] According to a specific embodiment of the present invention, the gas-liquid replacement chamber is located at the upper 1 / 3 of the pump cylinder 3.

[0061] According to a specific embodiment of the present invention, a middle sealing joint 4 is provided between the upper outer tube 2 and the replacement cavity tube 5, and a lower sealing joint 6 is provided between the replacement cavity tube 5 and the Tesla valve plate assembly.

[0062] Example 1

[0063] This invention provides an anti-airlock, low-leakage oil pump, which is used for installation on a tubing string and includes an upper connector 1, an upper outer tube 2, a short plunger structure, a pump barrel 3, a displacement chamber tube 5, a Tesla valve plate assembly, and a sealing assembly.

[0064] The upper connector 1 abuts against the upper part of the upper outer tube 2;

[0065] The pump cylinder 3, the displacement chamber tube 5, the Tesla valve plate group and the sealing assembly form an annular gas-liquid displacement chamber. The gas-liquid displacement chamber is located on the upper part of the pump cylinder 3 and is connected to the pump cylinder 3. The gas-liquid displacement chamber, the pump cylinder 3 and the upper outer tube 2 form an annular space.

[0066] The short plunger structure includes a sealing sleeve assembly 23, an adjusting back cap 24, and a short plunger 25. The short plunger structure is located inside the replacement chamber 5, and the sealing sleeve assembly 23, the adjusting back cap 24, and the short plunger 25 are arranged in order from top to bottom.

[0067] Example 2

[0068] Unlike Example 1, as Figure 1As shown, the oil pump adopts a low-leakage short plunger structure. The short plunger structure includes an upstream moving valve 18, a valve cover 19, a valve ball 20, a valve seat 21, a core tube 22, a sealing sleeve assembly 23, an adjusting back cap 24, a short plunger 25, and a valve seat pressure cap 26. The adjusting back cap 23 can adjust the clamping force of the sealing ring, allowing it to wobble and have a small axial clearance. The sealing sleeve assembly 23 consists of an outer sealing sleeve 27, an inner elastic sleeve 28, and a filler 29. The outer sealing sleeve 27 has an opening, allowing it to expand and contract elastically. Its outer surface is precision ground to achieve high hardness, improving the pump's durability and efficiency. The inner elastic sleeve 28 also has an opening, allowing it to expand and contract elastically. Its elasticity helps to fit tightly against the pump barrel 3, eliminating gaps and reducing leakage. Specific leakage tests are as follows:

[0069] Low-leakage short plunger structure leakage test: For oil pumps that have passed the sealing performance test, the leakage test medium is No. 0 or No. -10 diesel oil, with a kinematic viscosity of 3 mmHg at 20℃. 2 / s-8mm 2 / s, the standard plunger sealing surface length is 1.2m, grade 3, pump barrel 44.45, standard maximum leakage is 1060 (mL / min), the selected plunger is placed in the pump barrel, one end is connected to the test pressure connector, the other end is screwed into the special connector, the pump is placed in a horizontal position, and the leakage is measured under a pressure of not less than 10MPa. The standard maximum leakage is 1060 (mL / min), and the average of 10 tests is 952 (mL / min). The low leakage plunger pump sealing surface length is 0.15m, grade 3, pump barrel 44.45, and the average of 10 tests is 55 (mL / min). The leakage of the low leakage plunger pump is about 1 / 20 of that of the ordinary pump.

[0070] Example 3

[0071] Unlike Embodiments 1 and 2, the Tesla valve assembly includes a sealing cap 7, a valve housing 8, a valve 9, and a lower outer tube 10, which are arranged sequentially from top to bottom.

[0072] The pump cylinder 3 has an elongated hole at the bottom, and the valve plate housing 8 has a small hole drilled on it to form an exhaust channel with the valve plate 9. The flow channel is a Tesla valve structure.

[0073] The exhaust channels are arranged in two groups at a preset angle, and the two groups of valve plates 9 are stacked at a preset angle. A spacer is set between the two groups of valve plates. Each group consists of two valve plates and a spacer, forming a series Tesla channel inside. The Tesla valve is composed of multiple groups, which can greatly lengthen the exhaust flow channel of the Tesla valve structure.

[0074] The indoor test for Tesla valve assembly leakage is as follows:

[0075] Tesla valve assembly leakage test: The leakage test medium is either No. 0 or No. -10 diesel oil with a kinematic viscosity of 3 mmHg at 20°C. 2 / s-8mm 2 The leakage rate was measured at a pressure of not less than 10 MPa. With the valve plate installed in the forward direction, simulating liquid replenishment to the pump cylinder, the leakage rate was 210 mL / min. With valve plate 9 installed in the reverse direction, simulating leakage to the Tesla valve, the leakage rate was 85 mL / min. For the Tesla valve plate assembly, with valve plate 9 installed in the reverse direction, simulating venting, and using air as the medium, at 20℃ and a pressure of 0.8 MPa, the air leakage rate was 6000 mL / min, indicating good leakage prevention performance.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A low-leakage, airlock-proof oil pump, wherein the airlock-proof, low-leakage oil pump is used for mounting on a tubing string, characterized in that, Includes an upper connector (1), an upper outer tube (2), a short plunger structure, a pump barrel (3), a replacement chamber tube (5), a Tesla valve plate assembly, and a sealing assembly; The upper connector (1) abuts against the upper part of the upper outer tube (2); The pump cylinder (3), the displacement chamber tube (5), the Tesla valve plate group and the sealing assembly form an annular gas-liquid displacement chamber. The gas-liquid displacement chamber is located on the upper part of the pump cylinder (3) and communicates with the pump cylinder (3). The gas-liquid displacement chamber, the pump cylinder (3) and the upper outer tube (2) form an annular space. The short plunger structure includes a sealing sleeve assembly (23), an adjusting back cap (24), and a short plunger (25). The short plunger structure is located inside the replacement chamber (5), and the sealing sleeve assembly (23), adjusting back cap (24), and short plunger (25) are arranged in order from top to bottom.

2. The anti-airlock, low-leakage oil pump according to claim 1, characterized in that, The Tesla valve assembly is located on the bottom outer side of the pump barrel (3).

3. The anti-airlock, low-leakage oil pump according to claim 2, characterized in that, The Tesla valve assembly includes a sealing cap (7), a valve housing (8), a valve (9), and a lower outer tube (10), which are arranged sequentially from top to bottom.

4. The anti-airlock, low-leakage oil pump according to claim 2, characterized in that, The pump barrel (3) has an elongated hole at the bottom, and the valve plate housing (8) has a small hole drilled on it to form an exhaust channel with the valve plate (9). Its flow channel is a Tesla valve structure.

5. The anti-airlock, low-leakage oil pump according to claim 4, characterized in that, The exhaust channels are arranged into two groups at a preset angle, and the two groups of valve plates (9) are stacked at a preset angle. A spacer is provided between the two groups of valve plates. Each group consists of two valve plates and a spacer, and a series Tesla channel is formed inside. The Tesla valve is composed of multiple groups.

6. The anti-airlock, low-leakage oil pump according to claim 5, characterized in that, The sealing assembly includes a lower sealing joint (6), a compressible sealing ring (14), and a sealing ring cap (15), all of which are located on the outside of the pump barrel (3).

7. The anti-airlock, low-leakage oil pump according to claim 6, characterized in that, The compressible sealing ring (14) is disposed inside the lower sealing joint (6), and the sealing ring cap (15) is disposed below the lower sealing joint (6).

8. The anti-airlock, low-leakage oil pump according to claim 6, characterized in that, The short plunger structure includes an upstream valve assembly, a core tube (22), a downstream valve assembly, a sealing sleeve assembly (23), an adjusting back cap (24), and a short plunger (25). The upstream valve assembly and the downstream valve assembly are respectively disposed at the upper and lower parts outside the core tube (22). The core tube (22) is disposed inside the pump barrel. The sealing sleeve assembly (23), the adjusting back cap (24), the short plunger (25), and the sealing assembly are disposed between the upstream valve assembly and the downstream valve assembly.

9. The anti-airlock, low-leakage oil pump according to claim 8, characterized in that, The upstream valve assembly includes an upstream moving valve (18), a valve cover (19), a first valve ball (20), and a first valve seat (21). The upstream moving valve (18), the valve cover (19), and the first valve seat (21) are arranged sequentially from top to bottom outside the core tube (22), and the first valve ball (20) is arranged inside the core tube (22).

10. The anti-airlock, low-leakage oil pump according to claim 8, characterized in that, The sealing sleeve assembly (23), adjusting back cap (24), short plunger (25) and valve seat cap (26) are arranged sequentially below the upstream valve assembly.

11. The anti-airlock, low-leakage oil pump according to claim 8, characterized in that, The sealing sleeve assembly (23) includes an outer sealing sleeve (27), an inner elastic sleeve (28), and a filler (29), wherein the filler (29) is disposed between the outer sealing sleeve (27) and the inner elastic sleeve (28).

12. The anti-airlock, low-leakage oil pump according to claim 11, characterized in that, The outer sealing sleeve (27) has an opening and can expand and contract elastically. The outer surface friction coefficient of the outer sealing sleeve (27) is less than the preset friction coefficient. The hardness of the outer sealing sleeve (27) is greater than the preset hardness. The inner elastic sleeve (28) has an opening and can expand and contract elastically.

13. The anti-airlock, low-leakage oil pump according to claim 8, characterized in that, The downstream valve assembly includes a second valve ball (16), a second valve seat (17), a tailpipe connector (13), and a fixed valve assembly (12). The second valve ball (16) is disposed within the fixed valve assembly (12), the tailpipe connector (13) is disposed below the fixed valve assembly (12), and the second valve seat (17) is disposed between the tailpipe connector (13) and the fixed valve assembly (12).

14. The anti-airlock, low-leakage oil pump according to any one of claims 8-13, characterized in that, A set of sealing assemblies is provided below the upstream valve assembly and above the downstream valve assembly.

15. The anti-airlock, low-leakage oil pump according to claim 14, characterized in that, The gas-liquid replacement chamber is located at the upper 1 / 3 of the pump cylinder (3).

16. The anti-airlock, low-leakage oil pump according to claim 14, characterized in that, A middle sealing joint (4) is provided between the upper outer tube (2) and the replacement chamber tube (5), and a lower sealing joint is provided between the replacement chamber tube (5) and the Tesla valve plate assembly.

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